This article presents experimental results related to the influence of bioethanol content in fuel blends on the performance and emissions of a spark-ignition engine. Tests were conducted for six ethanol–gasoline mixtures (ranging from 0% to 100% ethanol) under three engine control strategies: factory settings, a fuel dose increased by 10%, and a fuel dose increased by 20%—both with an ignition timing adjustment of +3°. Measurements included engine power and torque, as well as emissions of CO, CO₂, HC, O₂, and particulate matter, all performed under a full engine load. The results revealed the strong dependence of engine behavior on ethanol content. Increasing the ethanol concentration significantly reduced CO and HC emissions, as well as markedly lowering particulate emissions—particularly at 30% ethanol. Conversely, pure ethanol led to substantial reductions in power (up to 28%) and torque (up to 32%) compared to conventional gasoline. Adjustments to the fuel dose and ignition timing partially mitigated these losses. Emissions of CO₂ and oxygen content in exhaust gases varied depending on the blend, highlighting the complex nature of the combustion process. The findings contribute to the understanding of renewable fuel behavior in SI engines and underscore the influence of both fuel composition and control strategies on performance and emission characteristics.

This article presents a study of the relationship between power and torque for a small spark-ignition outboard engine depending on the fuel used. The fuels considered here were gasoline with an octane number of 95, bioethanol in pure form, and mixtures of both fuels. Also studied were selected components of the exhaust gas generated during operation of the engine for each fuel. The results showed a decrease in the power and torque with an increase in the bioethanol content of the fuel, thus confirming the possibility of using both a bioethanol additive and bioethanol itself as a fuel to power the engine. The findings of the study clearly indicate that the use of an additive in the form of plant-based fuel significantly affects the reduction of emissions of harmful substances into the environment, for example reducing CO emissions by 67%, and HC by 56%. However, without design changes to the power systems, the reduction in emissions is achieved at the cost of a drop in power of more than 30%. This topic is currently important due to the tightening of regulations on emissions and recent research and implementation by engine manufacturers related to the development of electric propulsion systems, particularly for smaller vessels. However, restrictions on their applicability result in a continued need to use internal combustion engines.

The aim of the paper was to carry out measurements aimed at monitoring particulate matter emissions during vehicle braking. The results of the work compare and evaluate particulate matter emissions during braking on a cylindrical brake test bench. Using statistical analysis, the measured data were evaluated from the perspective of the established hypotheses. Based on comparing the results of experimental measurements carried out at braking forces F _b = 1 kN and F _b = 2 kN, it follows that the difference in the average size of particulate matter emissions is 1.53 nm, which represents approximately a 2.32% increase in the size of particulate matter emissions with an increase in braking force F _b . The results obtained from experimental measurements were analysed based on the established hypothesis and indicate that there is a significant difference in particulate matter emissions between braking forces F _b = 1 kN and F _b = 2 kN, with emissions being lower at braking force F _b = 1 kN.

The paper deals with the evaluation of service brake braking of a selected group of vehicles depending on the wear of brake system‘s parts. During the research, the technical condition of brake systems, the degree of wear of brake discs, brake pads, and the measurement of braking forces using a roller brake tester was monitored and evaluated on a sample of 16 intercity buses for a period of three years. The measurement was carried out on 2 selected intercity buses SOR C 10.5 and IVECO Crossway. The maximum braking forces on both axles of buses were measured using a roller brake tester. Then, the percentage braking of the vehicle was calculated and compared with the minimum required braking according to applicable legislation. Based on the inspection of technical condition of brake pads and discs, it was possible to detect the wear and tear of these elements of the brake system (which was manifested during the inspection of the vehicle on the roller brake tester), and it was also possible to record the insufficient value of the required minimum braking during the calculation.